1. Field of Invention
This invention relates to an image forming apparatus, and relates specifically to an ink-jet type image forming apparatus in which an image is formed by ejecting ink onto a recording medium such as paper.
2. Description of Related Art
Conventionally, an ink-jet type image forming apparatus has, for example, a recording medium transfer member that transfers paper and the like in a specified transfer direction and a recording head carriage arranged opposite a transfer path of the recording medium. The carriage is movable in a direction perpendicular to the transfer direction of the recording medium and ejects ink from the nozzles towards the transfer path of the recording medium.
Moreover, a full-color, ink-jet type image apparatus uses a recording head carriage capable of ejecting yellow ink, magenta ink, cyan ink and black ink. Further, the full-color, ink-jet type image apparatus generally comprises a plurality of nozzle components for each respective color and a plurality of ink tanks that supply ink to the nozzle components. Moreover, each of the nozzle components has a plurality of nozzles formed therein and each of the ink tanks is designed to be attachable to and detachable from the recording head carriage.
The ink-jet type image forming apparatus carries the recording medium using the recording medium transfer member. A prescribed image is formed on the recording medium by ejecting ink in accordance with image information while the recording medium is being transferred and the recording head carriage is being moved back-and-forth across the transfer path.
However, this type of ink-jet type image forming apparatus has various problems in maintaining image quality. Poor image quality is associated with the ink itself as well as its ejection from the nozzles to form the image.
Specifically, in the aforementioned ink-jet type image forming apparatus, first, the ink dries out in the nozzle components particularly when no images are being formed. When this condition occurs, the viscosity of the ink increases and, thus, the way the ink ejects from the nozzle components changes so that the desired image is not easily formed.
Second, in the aforementioned ink-jet type image forming apparatus, when foreign material or air enters the nozzles, the ink does not eject properly. Also, when the drying of the ink has progressed, the ink does not eject properly.
Third, in the aforementioned ink-jet type image forming apparatus, there are cases when the ink adheres to the tips of the nozzles specifically around the aperture edge of the nozzle. This occurs because the ink leaks from the nozzles due to a change of environmental conditions. When this condition occurs, the way the ink is ejected changes, and the desired image cannot be easily formed.
In the conventional ink-jet type image forming apparatus described above, these problems have been solved by providing a cap member that protects against the ink from drying out by covering the nozzle when images are not being formed. Also, a pump member is provided that sucks foreign material from the nozzle and a wiper member is provided that removes ink which adheres to the tip of the nozzle.
Moreover, in the aforementioned ink-jet type image forming apparatus, in order to solve these problems without obstructing the back-and-forth motion of the recording head carriage, it is necessary for the cap member to be capable of moving from a position in which the back-and-forth motion is not obstructed to a position in which the nozzles are covered, and to determine these positions. It is also necessary that the position of the pump member can be determined as it is moved from a position in which the back-and-forth motion is not obstructed to a position in which the pump member is connected to the nozzle. It is further necessary to perform the pumping operation when the pump member is connected to the nozzle. It is also necessary that the wiper member be capable of moving from a position in which the back-and-forth motion is not obstructed to a position where it contacts the nozzles. Also, it is necessary to be able to determine these positions of the wiper member.
However, it is difficult to reduce the size of such an apparatus since it is necessary to install each of these maintenance components.
Moreover, in the conventional ink-jet type image forming apparatuses, there are maintenance components that have a reduced size and are designed such that the cap member is connected to the pump and has a combined use for pumping. However, miniaturizing these maintenance components is difficult.